DESCRIPTION: Complete diagnostic evaluation (CDE) for persons with positive results on fecal occult blood testing (FOBT plus) is a key component of colorectal cancer screening. Experts consider CDE as either colonoscopy or double air-contrast barium enema x-ray (BE) with flexible sigmoidoscopy. These procedures require primary care physician (PCP) referral(s) to gastroenterologists and colorectal surgeons and/or to radiologists. However, PCP referral for CDE is infrequent. The investigators' survey results and pilot study data indicate that PCP practice factors and PCP misperceptions about indications for CDE are likely to impact CDE referral. They propose to study PCP referral of FOBT plus patients to CDE in an established HMO-based colorectal cancer screening program that involves annual FOBT mailings to 120,000 older adults (50 years of age) in Pennsylvania and New Jersey. The study has five phases: (1) conduct a PCP focus group to elucidate CDE-related issues and barriers and convene an expert panel to develop study interventions and validate patient CDE referral status; (2) administer a baseline and endpoint telephone survey to PCPs in HMO-affiliated practices; (3) conduct a randomized, controlled trial of interventions designed to improve CDE referral and completion (Control (N is equal to 120), Intervention Group 1 (N is equal to 120), Intervention Group 2 (N is equal to 120); (4) collect CDE data from PCP surveys and forms, medical chart audit, and administrative sources; and (5) analyze intervention impact and cost-effectiveness. Control Group practices will receive usual care (i.e., the USHC Colorectal Cancer Screening Program). Intervention Group 1 practices will receive usual care plus mailed CDE reminder-feedback. Intervention Group two practices will receive usual care, mailed CDE reminder-feedback, and two CDE academic detailing outreach visits.